Optimization method and system for soc cumulative error of lithium battery slow charging for a long time

Abstract

The embodiment of the present application provides a kind of lithium battery slow charging long time SOC cumulative error optimization method and system, belong to the charging monitoring technical field of lithium battery.The optimization method includes: the charging current of the lithium battery is obtained;Determine whether the charging current is in the preset interval range;In the case where it is judged that the charging current is in the preset interval range, the maximum value of the single battery voltage of the lithium battery in the first SOC interval is obtained every interval preset;Determine whether the number of the maximum value obtained is greater than the first number threshold;In the case where it is judged that the number of the maximum value is greater than the first number threshold, according to the change rate of the maximum value obtained in each predetermined second SOC interval, the first change rate sequence representing the change rate of the maximum value in each second SOC interval is obtained.The optimization method and system can accurately correct the SOC value of battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging monitoring of lithium batteries, in particular to a slow charging long time SOC cumulative error optimization method and system for lithium batteries. BACKGROUND

[0002] When the battery works for a period of time, the SOC will appear false high and false low due to the aging of the battery; the SOC value stored by the BMS cannot reflect the actual SOC value of the current battery. In order to solve this SOC false high and false low problem, the BMS will adopt dynamic calibration and static calibration strategy at present, obtain the current real SOC value by searching the SOC_OCV table, and then perform acceleration and deceleration calibration to realize the SOC of the BMS close to the real SOC until fitting.

[0003] The current dynamic calibration and static calibration strategy generally calibrates the false high or false low of the battery SOC in the slow charging small current charging process at the end of charging. If the user charges for a long time and disconnects the charging before the battery is fully charged, the SOC false high or false low problem cannot be well solved. In this way, the SOC cumulative error will be large after a long time, so that the battery SOC cannot be accurately estimated. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a slow charging long time SOC cumulative error optimization method and system for lithium batteries, which can accurately correct the SOC value of the battery.

[0005] In order to achieve the above purpose, the embodiment of the present application provides a slow charging long time SOC cumulative error optimization method for lithium batteries, comprising:

[0006] Obtaining the charging current of the lithium battery;

[0007] Judging whether the charging current is located in a preset interval range;

[0008] In the case where it is judged that the charging current is located in the preset interval range, the maximum value of the single cell voltage of the lithium battery in the first SOC interval is obtained every preset first SOC interval;

[0009] Judging whether the number of the maximum values obtained is greater than a preset first number threshold;

[0010] In the case where it is judged that the number of the maximum values is greater than the first number threshold, a first change rate sequence representing the change rate of the maximum values in each second SOC interval is obtained according to the change rate of the maximum values in each predetermined second SOC interval, wherein the length of the second SOC interval is equal to twice the length of the first SOC interval;

[0011] determining whether the number of the first SOC intervals currently obtained is greater than or equal to a preset second number threshold;

[0012] in a case where it is determined that the number of the first SOC intervals currently obtained is greater than or equal to the preset second number threshold, calculating a second change rate sequence of the first change rate sequence according to formula (1),

[0013] (1)

[0014] wherein, is a second change rate in the second change rate sequence, is a first change rate in the first change rate sequence, is a serial number;

[0015] determining whether the first to fourth second change rates in the second change rate sequence are all less than 0;

[0016] in a case where it is determined that the first to fourth second change rates in the second change rate sequence are all less than 0, determining whether a fifth second change rate in the second change rate sequence is greater than or equal to 0;

[0017] in a case where it is determined that the fifth second change rate in the second change rate sequence is greater than or equal to 0, determining whether the sixth to eighth second change rates in the second change rate sequence are all greater than 0;

[0018] in a case where it is determined that the sixth to eighth second change rates in the second change rate sequence are all greater than 0, determining whether a fifth change rate of the first change rate sequence is greater than or equal to a preset change rate threshold;

[0019] in a case where it is determined that the fifth change rate is greater than or equal to the change rate threshold, determining that a third first SOC interval obtained is the SOC inflection point;

[0020] calculating an absolute value of a difference between the SOC inflection point and a first SOC at which the change rate of the single cell voltage of the lithium battery is maximum;

[0021] determining whether the absolute value of the difference is less than a preset first threshold;

[0022] in a case where it is determined that the absolute value of the difference is less than the first threshold, correcting the SOC inflection point to the first SOC.

[0023] Optionally, the optimization method further comprises:

[0024] obtaining a correspondence table of SOC and single cell voltage of a lithium battery;

[0025] redetermine the correspondence table according to a preset first SOC interval;

[0026] calculate the rate of change of the single cell voltage;

[0027] select the SOC value at the left end of the first SOC interval with the maximum rate of change of the single cell voltage as the first SOC.

[0028] Optionally, the optimization method further comprises:

[0029] obtain a correspondence table of the SOC and the single cell voltage of the lithium battery;

[0030] redetermine the correspondence table according to a preset first SOC interval;

[0031] calculate the rate of change of the single cell voltage;

[0032] select the SOC value at the right end of the first SOC interval with the maximum rate of change of the single cell voltage as the first SOC.

[0033] Optionally, the optimization method further comprises:

[0034] in the case where it is judged that the absolute value of the difference is greater than or equal to the first threshold value, judge whether the single cell voltage corresponding to the SOC inflection point is greater than or equal to the single cell voltage corresponding to the first SOC;

[0035] in the case where it is judged that the single cell voltage corresponding to the SOC inflection point is greater than or equal to the single cell voltage corresponding to the first SOC, accelerate the charging integral by 0.8 times;

[0036] Optionally, the optimization method further comprises:

[0037] in the case where it is judged that the single cell voltage corresponding to the SOC inflection point is less than the single cell voltage corresponding to the first SOC, accelerate the charging integral by 1.2 times.

[0038] Optionally, the optimization method further comprises:

[0039] judge whether the current correction amount is equal to the absolute value of the difference;

[0040] in the case where it is judged that the correction amount is equal to the absolute value of the difference, end the current correction process;

[0041] judge whether the current correction amount is equal to the absolute value of the difference;

[0042] in the case where it is judged that the correction amount is not equal to the absolute value of the difference, return to execute the step of obtaining the charging current of the lithium battery again until it is judged that the correction amount is equal to the absolute value of the difference.

[0043] Optionally, the first SOC interval is 1%, the interval range is [-11A, -6A], the second SOC interval is 1%, the first number threshold is 2, and the second number threshold is 10.

[0044] Optionally, the optimization method further comprises:

[0045] acquiring a current temperature of the lithium battery;

[0046] judging whether the temperature is greater than or equal to 10 degrees Celsius;

[0047] in a case where it is judged that the temperature is greater than or equal to 10 degrees Celsius, adjusting the change rate threshold to 0.003;

[0048] in a case where it is judged that the temperature is less than 10 degrees Celsius, adjusting the change rate threshold to 0.002.

[0049] In another aspect, the present application also provides a lithium battery slow charging long time SOC cumulative error optimization system, which comprises a processor, and the processor is used for executing the optimization method according to any one of the above.

[0050] In still another aspect, the present application also provides a computer readable storage medium, which stores instructions for being read by a machine to make the machine execute the optimization method according to any one of the above.

[0051] Through the above technical solution, the optimization method and system for lithium battery slow charging long time SOC cumulative error provided by the present application realize accurate correction of the SOC of the lithium battery by acquiring the voltage change state of the lithium battery in the slow charging process and comparing the change state with the change characteristics of the lithium battery itself.

[0052] Other features and advantages of the embodiments of the present application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0053] The accompanying drawings are included to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used together with the following specific implementation part to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0054] Figure 1 is a flowchart of the optimization method for lithium battery slow charging long time SOC cumulative error according to an embodiment of the present application;

[0055] Figure 2 is a partial flowchart of the optimization method for lithium battery slow charging long time SOC cumulative error according to an embodiment of the present application;

[0056] Figure 3 is a part of flow chart of the optimization method of long-time SOC cumulative error of lithium battery slow charging according to an embodiment of the present application. DETAILED DESCRIPTION

[0057] The specific embodiments of the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the embodiments of the present application, and are not intended to limit the embodiments of the present application.

[0058] As shown in Figure 1 is a flow chart of the optimization method of long-time SOC cumulative error of lithium battery slow charging according to an embodiment of the present application. In this Figure 1 , the optimization method can include:

[0059] In step S10, the charging current of the lithium battery is obtained;

[0060] In step S11, it is judged whether the charging current is within a preset interval range;

[0061] In step S12, in the case where it is judged that the charging current is within the preset interval range, the maximum value of the single cell voltage of the lithium battery within a first SOC interval is obtained every preset first SOC interval;

[0062] In step S13, it is judged whether the number of the obtained maximum values is greater than a preset first number threshold;

[0063] In step S14, in the case where it is judged that the number of the maximum values is greater than the first number threshold, a first rate of change sequence representing the rate of change of the maximum values within each second SOC interval is obtained according to the rate of change of the obtained maximum values within each predetermined second SOC interval, wherein the length of the second SOC interval is equal to twice the length of the first SOC interval;

[0064] In step S15, it is judged whether the number of the currently obtained first SOC intervals is greater than or equal to a preset second number threshold;

[0065] In step S16, in the case where it is judged that the number of the currently obtained first SOC intervals is greater than or equal to the preset second number threshold, a second rate of change sequence of the first rate of change sequence is calculated according to formula (1),

[0066] , (1)

[0067] wherein, is a second rate of change in the second rate of change sequence, is a first rate of change in the first rate of change sequence, For serial numbers;

[0068] In step S17, it is determined whether the first to fourth second rates of change in the second rate of change sequence are all less than 0;

[0069] In step S18, if it is determined that the first to fourth second rates of change in the second rate of change sequence are all less than 0, it is determined whether the fifth second rate of change in the second rate of change sequence is greater than or equal to 0.

[0070] In step S19, if it is determined that the fifth second rate of change in the second rate of change sequence is greater than or equal to 0, it is determined whether the sixth to eighth second rates of change in the second rate of change sequence are all greater than 0.

[0071] In step S20, if it is determined that the sixth to eighth second rates of change in the second rate of change sequence are all greater than 0, it is determined whether the fifth rate of change in the first rate of change sequence is greater than or equal to a preset rate of change threshold.

[0072] In step S21, if the fifth rate of change is greater than or equal to the rate of change threshold, the obtained third first SOC interval is determined as the SOC inflection point.

[0073] In step S22, the absolute value of the difference between the SOC inflection point and the first SOC with the largest single-cell voltage change rate of the lithium battery is calculated.

[0074] In step S23, it is determined whether the absolute value of the difference is less than a preset first threshold.

[0075] In step S24, if the absolute value of the difference is less than the first threshold, the SOC inflection point is corrected to the first SOC.

[0076] In such Figure 1 In the method shown, steps S10 and S11 can be used to determine whether the lithium battery is in a slow charging state. Since the conventional charging states of a lithium battery include fast charging and slow charging, in fast charging, the charging current of the lithium battery remains constant; in slow charging, the current of the lithium battery gradually decreases, while the charging voltage remains constant. The fact that the user has not fully charged the lithium battery for a long time, as mentioned in the background art, refers to the lithium battery's charging current not decreasing to a preset current value. Therefore, by judging the range of the charging current, it is possible to determine whether the current lithium battery is in a slow charging state. While this range can be multiple values ​​known to those skilled in the art, considering the lithium battery involved in this invention, in one example of this invention, the range can be, for example, [-11A, -6A].

[0077] Step S12 and step S13 can determine whether the number of currently acquired cell voltages is sufficient to calculate the rate of change. Specifically, the curve of the cell voltages of the lithium battery can be divided by the preset first SOC interval, and the maximum value of the cell voltages in each first SOC interval can be taken to represent the characteristics of the cell voltages in the first SOC interval. Similarly, the minimum value of the cell voltages in each first SOC interval can also be taken to represent the characteristics of the cell voltages in the first SOC interval. The first number threshold can be a plurality of values known to those skilled in the art, such as 2, 3, 4, 5, etc. In an example of the present application, the first number threshold can be 2. In the case where step S13 determines that the number of currently acquired cell voltages is less than the first number threshold, it means that at least one rate of change cannot be calculated. Therefore, it is necessary to return to step S10. In addition, in order to ensure that the first SOC interval corresponding to the acquired cell voltage is continuous, in the case where it is determined that the number of currently acquired cell voltages is less than the first number threshold, all the cell voltages in the current cache need to be cleared and re-counted.

[0078] Steps S14 to S15 can be used to determine whether the cell voltages corresponding to the currently acquired first SOC interval can reflect the characteristics of the cell voltages changing with the SOC. Specifically, the cell voltages of the lithium battery can be divided by the preset second SOC interval. In order to show the change characteristics of the cell voltages in different first SOC intervals, the second SOC interval can be equal to twice the first SOC interval. In an example of the present application, in the case where the first SOC interval is equal to 1%, the second SOC interval can be equal to 2%. Step S16 can be used to calculate the second rate of change sequence of the rate of change of the first rate of change sequence representing the rate of change of the cell voltages, i.e. using formula (1). Although the second number threshold involved in step S15 can also be a plurality of values known to those skilled in the art, considering the judgment logic of subsequent steps S17 to S20, in an example of the present application, the second number threshold can be 10.

[0079] The steps S17 to S20 can determine the position of the SOC inflection point through the feature judgment of the calculated second change rate sequence. The judgment logic of the SOC inflection point from the steps S17 to S20 can be obviously seen that it is actually the point of the maximum change rate of the single cell voltage of the lithium battery in the slow charging process. For the change rate threshold value involved in the steps S17 to S20, although it can be a plurality of point values known by those skilled in the art. However, in the process of implementing the technical scheme of the present application, the inventor found that when the lithium battery is at different temperatures, the change rate threshold value also needs to be adjusted accordingly. Therefore, in one preferred example of the present application, the method for determining the change rate threshold value can be to first obtain the current temperature of the lithium battery; and then judge whether the obtained temperature is greater than or equal to 10 degrees Celsius. In the case where the temperature is greater than or equal to 10 degrees Celsius, the change rate threshold value is adjusted to 0.003; and in the case where the temperature is less than 10 degrees Celsius, the change rate threshold value is adjusted to 0.002. In addition, in the case where any of the judgment logics of the steps S17 to S20 is no, at this time, in order to ensure that the obtained second change rate sequence is continuous, it is necessary to return to execute the step 10.

[0080] Finally, the step S22 determines the correction operation currently required to be performed by calculating the absolute value of the difference between the SOC inflection point and the single cell voltage corresponding to the first SOC with the maximum single cell voltage change rate, and comparing the absolute value of the difference with the size relationship of the first threshold value. For the first threshold value, similarly as mentioned above, although it can also be a plurality of point values known by those skilled in the art. However, in one example of the present application, the first threshold value can be 20%.

[0081] In the case where the absolute value of the difference is less than the first threshold value, at this time, it indicates that the SOC estimation deviation of the current lithium battery is not large, and therefore the SOC inflection point can be directly corrected to the first SOC.

[0082] In the case where the absolute value of the difference is greater than or equal to the first threshold value, at this time, it indicates that the SOC estimation deviation of the lithium battery is large, and therefore further comparison and judgment of the single cell voltage of the lithium battery is required to determine how to correct the SOC. That is, in the case where the absolute value of the difference is greater than the first threshold value, it is judged whether the single cell voltage corresponding to the SOC inflection point is greater than or equal to the first SOC. In the case where the single cell voltage corresponding to the SOC inflection point is greater than or equal to the first SOC, at this time, it indicates that the charging integral estimation of the SOC is too fast, and therefore the charging integral can be corrected to the current 0.8 times. Conversely, in the case where the single cell voltage corresponding to the SOC inflection point is less than the first SOC, at this time, it indicates that the charging integral estimation of the SOC is slow, and therefore the charging integral can be corrected to the current 1.2 times.

[0083] In one embodiment of the present application, in order to avoid the optimization method provided by the present application from being repeatedly executed, after each correction, it can be further determined whether the current correction amount is equal to the absolute value of the difference; in the case where the correction amount is equal to the absolute value of the difference, it is indicated that the current correction error is very small, and thus the current correction process can be ended; in the case where the correction amount is not equal to the absolute value of the difference, it is indicated that correction is still needed, and thus the step of obtaining the charging current of the lithium battery can be returned to be executed again until the correction amount is equal to the absolute value of the difference.

[0084] In this embodiment, for the above-mentioned first SOC obtaining method, there are various methods known by those skilled in the art. In one example of the present application, the obtaining method can be the method shown in Figure 2 or Figure 3 In this Figure 2 , the obtaining method can include:

[0085] In step S30, a correspondence table of the SOC and the single cell voltage of the lithium battery is obtained;

[0086] In step S31, the correspondence table is re-divided into preset first SOC intervals;

[0087] In step S32, the rate of change of the single cell voltage is calculated;

[0088] In step S33, the SOC value at the left end of the first SOC interval with the largest rate of change of the single cell voltage is selected as the first SOC.

[0089] In Figure 3 , the obtaining method can include:

[0090] In step S40, a correspondence table of the SOC and the single cell voltage of the lithium battery is obtained;

[0091] In step S41, the correspondence table is re-divided into preset first SOC intervals;

[0092] In step S42, the rate of change of the single cell voltage is calculated;

[0093] In step S43, the SOC value at the right end of the first SOC interval with the largest rate of change of the single cell voltage is selected as the first SOC.

[0094] On the other hand, the present application also provides a lithium battery slow charging long-time SOC cumulative error optimization system, which comprises a processor, and the processor is used to execute the optimization method as described in any one of the above.

[0095] In still another aspect, the present application also provides a computer readable storage medium storing instructions for being read by a machine to cause the machine to perform the optimization method according to any one of the above aspects.

[0096] By the technical solution, the optimization method and system for long-time SOC cumulative error of slow charging of a lithium battery provided by the present application can realize accurate correction of the SOC of the lithium battery by acquiring the voltage change state of the lithium battery in the slow charging process and comparing the change state with the change characteristics of the lithium battery itself.

[0097] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0098] The present application is described with reference to the flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The means for implementing the functions specified in the flowcharts and / or block diagrams Figure 1 The means for implementing the functions specified in the flowcharts and / or block diagrams

[0099] These computer program instructions can also be stored in a computer-readable memory capable of causing the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The means for implementing the functions specified in the flowcharts and / or block diagrams Figure 1 The means for implementing the functions specified in the flowcharts and / or block diagrams

[0100] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The means for implementing the functions specified in the flowcharts and / or block diagrams Figure 1steps of a function specified in one or more blocks.

[0101] In one typical arrangement, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0102] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) about which the processor can execute instructions. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, or other memory technologies, about which the processor can execute instructions. The memory can be a memory storage device of any type.

[0103] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EEPROM), flash memory or other memory technologies, compact disc read only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media such as modulated data signals and carrier waves.

[0104] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to encompass a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0105] The above merely provides an embodiment of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method for optimizing long-term SOC cumulative error of lithium battery slow charging, characterized in that, The optimization method comprises: obtaining a charging current of the lithium battery; determining whether the charging current is within a preset interval range; in a case where it is determined that the charging current is within the preset interval range, obtaining a maximum value of a single cell voltage of the lithium battery within a preset first SOC interval every time the first SOC interval is obtained; determining whether the number of the maximum values obtained is greater than a preset first number threshold; in a case where it is determined that the number of the maximum values is greater than the first number threshold, obtaining a first rate sequence representing a rate of change of the maximum values in each second SOC interval according to a rate of change of the maximum values obtained in each second SOC interval, wherein a length of the second SOC interval is equal to twice a length of the first SOC interval; determining whether a number of the first SOC intervals currently obtained is greater than or equal to a preset second number threshold; in a case where it is determined that the number of the first SOC intervals currently obtained is greater than or equal to the preset second number threshold, calculating a second rate sequence of the first rate sequence according to formula (1), ，（1） wherein is a second change rate in the sequence of second change rates, is a first change rate in the sequence of first change rates, is a sequence number; determining whether the first to fourth second rates in the second rate sequence are all less than 0; in a case where it is determined that the first to fourth second rates in the second rate sequence are all less than 0, determining whether a fifth second rate in the second rate sequence is greater than or equal to 0; in a case where it is determined that the fifth second rate in the second rate sequence is greater than or equal to 0, determining whether the sixth to eighth second rates in the second rate sequence are all greater than 0; in a case where it is determined that the sixth to eighth second rates in the second rate sequence are all greater than 0, determining whether a fifth rate of the first rate sequence is greater than or equal to a preset rate threshold; in a case where it is determined that the fifth rate is greater than or equal to the rate threshold, determining that a third first SOC interval obtained is the SOC inflection point; calculating an absolute value of a difference between the SOC inflection point and a first SOC at which a rate of change of the single cell voltage of the lithium battery is maximum; determining whether the absolute value of the difference is less than a preset first threshold; in a case where it is determined that the absolute value of the difference is less than the first threshold, correcting the SOC inflection point to the first SOC. The optimization method further comprises: obtaining a correspondence table of an SOC and a single cell voltage of a lithium battery; re-dividing the correspondence table by a preset first SOC interval; calculating a rate of change of the single cell voltage; selecting an SOC value at a left end of the first SOC interval with the maximum rate of change of the single cell voltage as the first SOC.

2. The optimization method of claim 1, wherein, The optimization method further comprises: obtaining a correspondence table of an SOC and a single cell voltage of a lithium battery; re-dividing the correspondence table by a preset first SOC interval; calculating a rate of change of the single cell voltage; selecting an SOC value at a right end of the first SOC interval with the maximum rate of change of the single cell voltage as the first SOC.

3. The optimization method of claim 1, wherein, The optimization method further comprises: In a case where it is judged that the absolute value of the difference is greater than or equal to the first threshold value, it is judged whether the single battery voltage corresponding to the SOC inflection point is greater than or equal to the single battery voltage corresponding to the first SOC. In a case where it is judged that the single battery voltage corresponding to the SOC inflection point is greater than or equal to the single battery voltage corresponding to the first SOC, the charging integral is accelerated by 0.8 times.

4. The optimization method of claim 3, wherein, The optimization method further comprises: In a case where it is judged that the single battery voltage corresponding to the SOC inflection point is less than the single battery voltage corresponding to the first SOC, the charging integral is accelerated by 1.2 times.

5. The optimization method of claim 1, wherein, The optimization method further comprises: It is judged whether the current correction amount is equal to the absolute value of the difference; In a case where it is judged that the correction amount is equal to the absolute value of the difference, the current correction process is ended; It is judged whether the current correction amount is equal to the absolute value of the difference; In a case where it is judged that the correction amount is not equal to the absolute value of the difference, the step of obtaining the charging current of the lithium battery is executed again until it is judged that the correction amount is equal to the absolute value of the difference.

6. The optimization method of claim 1, wherein, The first SOC interval is 1%, the interval range is [-11A, -6A], the second SOC interval is 1%, the first number threshold value is 2, and the second number threshold value is 10.

7. The optimization method of claim 1, wherein, The optimization method further comprises: The current temperature of the lithium battery is obtained. It is judged whether the temperature is greater than or equal to 10 degrees Celsius. In a case where it is judged that the temperature is greater than or equal to 10 degrees Celsius, the change rate threshold value is adjusted to 0.

003. In a case where it is judged that the temperature is less than 10 degrees Celsius, the change rate threshold value is adjusted to 0.

002.

8. A system for optimizing long-term SOC accumulation error of lithium battery slow charging, characterized in that, The optimization system comprises a processor configured to execute the optimization method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions for being read by a machine to cause the machine to execute the optimization method according to any one of claims 1 to 7.

Images